The circulatory system transports oxygen, nutrients, hormones, and antibodies throughout the body while removing waste. It consists of the heart, blood, and blood vessels. The heart pumps blood through three circulation loops - pulmonary circulation to the lungs, coronary circulation to the heart itself, and systemic circulation to the rest of the body. Blood travels from the heart through arteries, then into capillaries where nutrients and waste are exchanged, then into veins which return blood back to the heart.